Generally speaking, an electric machine such as an electric motor or a dynamo comprises a stator, a rotor mounted on a shaft and a casing which has supports for the rotor shaft.
To mount the stator and the rotor in the casing, the casing must be separated into at least two parts which can be put together.
An example of an electric machine and of a method for its production is known from U.S. Pat. No. 5,767,596.
Electric motors that are water- and humidity-proof are also known, especially in the sector of electric fans for motor vehicles.
Due to the environmental conditions and the position of electric fans close to heat sources and/or cold sources, the humidity in the environment may penetrate the motor casing and following temperature variations it may be transformed into liquids, creating electrical problems for the motor.
Starting with the typical construction of the motor casing in two parts, of which one part is cup-shaped and the other part is lid-shaped, attempts were made to produce a waterproof casing for electric motors, inserting a seal between the above-mentioned two parts.
However, this type of assembly is not without disadvantages: indeed, the insertion of a seal complicates the structure of the motor.
In addition, for motor casing sealing to be effective, the seal must be correctly positioned between the two parts, which must also have suitable housings for the seal.